This invention relates to heat exchanging systems in which a recirculating fluid refrigerant absorbs heat at an evaporator and releases heat at a condenser. More particularly the invention relates to apparatus for processing the refrigerant flow between the condenser and the evaporator in order to enhance the efficiency of the system.
Heat exchanging systems to which the invention is applicable include refrigerating systems, air conditioning systems and heat pumping systems among other examples. Systems of this kind have a motor driven compressor which pressurizes gaseous fluid that is received from an evaporator coil. The pressurizing raises the temperature of the fluid which is then transmitted to a condenser coil. The fluid releases heat into the region which is adjacent to thee condenser coil and condenses to liquid form as it cools. The condensed and cooled fluid is then returned to the evaporator coil where it expands and absorbs more heat from the region adjacent to the evaporator coil. Thus heat removed from the region adjacent to the evaporator coil is transferred to the region adjacent to the condenser coil.
Operation of the motor which drives the compressor consumes costly energy. Energy can be saved and operating costs can be reduced by increasing the thermodynamic efficiency of the system. It has heretofore been recognized that the energy which is required to transfer a given amount of heat at a given rate is affected by the compression ratio at the compressor and by the temperature of the condensed fluid as it enters the evaporator coil. Any steps which enable the compressor to deliver the fluid to the condenser coil at a lower head pressure increases efficiency. A lower fluid temperature at the inlet of the evaporator coil enables absorption of a greater amount of heat in the evaporator coil and thereby further increases efficiency.
It has also been recognized that the required compression ratio and also the temperature at the inlet of the evaporator coil can both be lowered by flow processing means in the flow path from the condenser coil to the evaporator coil. Prior U.S. Pat. No. 5,426,956 discloses flow processing means for this purpose, the specification and drawings of that patent being herein incorporated by reference. The flow processing means of that prior patent include a vessel which receives the condensed fluid from the condenser coil and delivers the fluid to the expansion valve and evaporator coil. The vessel holds a volume of condensed fluid that may otherwise be backed up into the condenser coil and thereby provides for increased condensation within the condenser coil. Further condensation takes place in the vessel itself. The increased condensation raises efficiency by lowering the discharge pressure at the outlet of the compressor. Heat transfer through the wall of the vessel results in further cooling of the condensed fluid and the heat transfer is enhanced by configuring the vessel to swirl the flow in a vortex as it travels toward the outlet of the vessel. Further cooling occurs by heat transfer through the wall of the conduit which delivers the condensed fluid from the vessel to the expansion valve and evaporator coil. In the apparatus of the above identified prior patent, a turbulator element at the outlet of the vessel enhances this further cooling by enhancing the rotational motion of the flow as it enters the conduit. Flow turbulence this kind increases heat loss through the conduit wall as the flow travels along the conduit thereby causing further cooling of the flow.
The presence of the turbulence inducing element in the flow path causes some back pressure which must be counteracted by the compressor. An object of this invention is to provide further energy saving and operating cost reduction by increasing turbulence in the flow which is discharged from the vessel and by reducing the back pressure which is created by the turbulence increasing component.
The present invention is directed to overcoming one or more of the problems discussed above.
In one aspect the present invention provides a flow processing vessel having an inlet for receiving a flow of liquefied refrigerant from a refrigerant condenser having an outlet for delivering a flow of the liquefied refrigerant to an expansion device and evaporator through an outlet conduit. The vessel is configured to provide vortex rotation of the liquid as it travels downward from the inlet towards the outlet and has a turbulence enhancing component at the outlet for causing turbulence of the flow within the outlet conduit. The turbulence enhancing component has a flow guiding member with a helical inner surface that extends vertically within the flow at the outlet and which is oriented to impart rotational motion to the flow as it passes downward through the outlet.
In another aspect of the invention, a refrigerant flow processor includes a vessel forming an upright cylindrical vortex chamber and having a fluid inlet at an upper region thereof and a fluid outlet at the center of a bottom portion thereof. A flow delivery tube extends from the fluid inlet within the chamber, the tube being angled to direct incoming refrigerant towards a side region of the vortex chamber to reinforce rotation of fluid flow therein. An upright coupling sleeve extends downward from the fluid outlet and is adapted to receive a fluid outflow conduit. A vortex generator extends downward through the outlet and into an upper region of the coupling sleeve. The vortex generator has a flow guiding member with a helical inner surface which is curved to conform with the path of the liquid flow which is undergoing vortex rotation and descending through the outlet.
The invention reduces the discharge pressure at the compressor and lowers the temperature of the refrigerant which enters the expansion valve and evaporator. Power consumption by the motor driven compressor is thereby reduced to realize a substantial reduction in the operating cost of the system.